Oven controlled Xtal Oscillators (OCXOs) are used in high frequency applications. The Double oven construction ensures a stable operating temperature, diminishing temperature fluctuations that would affect the function of the piezoelectric resonator, introducing error into the frequency. The double oven configuration operates by maintaining both ovens above the maximum operating ambient temperature. The crystal characteristics are matched to this temperature for operation at a 0 slope point on the frequency— temperature curve. This curve is commonly represented by a third or fourth order polynomial describing the dependence of frequency on temperature. The nature of this dependency results in even small fluctuations in temperature producing noticeable effects on frequency stability.
Placing the oscillator crystal within two ovens allows the secondary (external oven) to insulate the primary oven (internal) from ambient temperature fluctuations. Such a system, is however, complex and expensive to build, requiring multiple printed circuit boards. Associated with multiple boards are the complexities of connecting those boards. The use of multiple boards also demands larger packages, complicating efforts to decrease the volume of the housing.
What is needed, therefore, are techniques for providing temperature stability for an oscillator device configured on a single printed circuit board.